Telegraph.



A. HJORT.

TELEGRAPH.

APPLICATION FILED APR. I. 1912 Patented Dec. 7, 1915.

INVENTOR WITNESSES M ATToriN W5 cairn srs Pannier F150.

ALF H-TORT, or NEW YORK, N. Y., assIeNoR or ,oNn-rounrn 'ro HENRY .mrr, on NEW roan, N. Y.

TELEGRAPH.

Specification of Letters Patent.

Patented Dec. '3, 1915.

Application filed April 1, 1912. Serial No. 687,701.

To all whom it may concern:

Be it known that I, ALF HJoR'r, a subject of the King of Norway, and residing in the city, county, and State of New York, have invented a certain new and useful Improve ment in Telegraphs, of which the following is a specification.

My invention relates to telegraphs and the object of my invention is to provide a telegraph system and apparatus in which an alternating current may be successfully employed.

My invention contemplates the transmission of alternating currents of predetermined frequency to a receiving appliance which comprises vibrators tuned to respond to the varying frequencies of the currents transmitted and preferably adapted to automatically effect the record of a corresponding series of symbols or letters.

In the accompanying drawing my invention is illustrated in a diagrammatic embodiment thereof in one form.

The basis of the present system is the discovery that a reed of steel or other suitable material having a certain predetermined frequency of vibration may be set in motion by subjecting it to the influence of an alternating current of coinciding frequency.

' Briefly, the transmitting apparatus con-.

sists of a source of alternating electricLcur rent, the frequency of which canbe selected at will. The receiving apparatus consists of a coil through which the alternating currents are passed, and supported within the coil a series of steel vibrators or reeds of predetermined various frequencies. When a current of selected frequency is passed through the coil from the transmitter, the reed of corresponding frequency will be set in motion. This vibration of the reeds may be utilized to effect the record of different symbols, for example'a difierent letter of the alphabet for each reed, so that the messages may be thus transmitted and recorded.

In the particular form diagrammatically shown in the drawing, the transmittercomprises a constant speed motor 10 which drives a series of alternating current generators-A to I, of small size and uniform make, but each at a different speed from the other. The speeds of these generators are so regulated and positively determined through a proper regulation of the gears the keyboard of a typewriter) so that upon the depression of any one of the keys A to I the line circuit is closed through that particular generator, by reason offits engagement with one of the various terminals 18 for the line Wire 16. It is thus obvious that a series of currents of difi'erent frequencies maybe passed over the line wires by the temporary closing of the various switches A to I in the order desired.

The receiving apparatus as illustrated comprises a receiving coil 19 connected to the line wires 15, 16, or the connection to line 15 grounded. Longitudinally within the coil are arranged a series of reeds 20 20*,20 corresponding in number to the number of generators and each having a quency of the particular generator to which 19, by the depression of a particular key A .causes the corresponding reed20" to vibrate at the receiving apparatus. Thereeds may be carried by brackets 21 in which they are adjustably secured by clamping screws 22, so that they may be accurately tuned to the desired frequency. v

The record effected by the vibration of the reed may besecured in any desired way. An arrangement is shown in connection with reed 20' for automatically effecting the actuation of typewriter keys. To this end, an auxiliary circuitis used which may be derived from any suitable source 23. Two electro-magnets 24 and 25 are arranged in, this circuit the one (24) positioned above a lever 26 attached to a typewriter key lever 27 and the other (25) positioned above one end of a damping lever-.28. The circuit is normally broken between a contact 29 and the frequency of vibration tuned to the freis tuned to the frequency of this generator, no

vibrates. This vibration closes the auxiliary circuit through thecontact 29- thereby -energizing the elect'ro-magnet 24. This rocks-the lever 26 on its pivot and depresses the key'lever 27 thus printing the letter aof the typewriter. The small mag net 25 is simultaneouslyenergized, with the result that the damping lever 28 is attracted and rocked on its pivot whereby the end overlying the reed 20 is momentarily pressed down upon the latter to check its vibration and prevent repeated contact with the terminal 29. This particular arrangement is merely illustrative of-an automatic recording device operated by the vibration of the rods 20, etc., and is by no means to be regarded as the only arrangement con templated by, me.

In transmitting messages over long distanc'es, the current passing between the;

transmitter and receiver may be stepped to a high voltage by stationary transformers in a manner well understood by thoseskilled in the art and stepped down again at the receiving end, thus savingin the weight of long distance transmission lines.

If it is desired-to send more than one message over .theline at once,,.it is only necessary to build the transmitters and rerange can be reduced or lengthened as be found advisable.

I claim as my invention 1. A telegraph system comprising 'a' group of alternating current generators of various predetermined frequencies, a and selective means for energizing the line circuit therefrom, in combination with a receiving coil in the line circuit and a group of vibrators arranged within magnetic field of said coil and variously tuned to the frequencies of said generators.

2. A telegraph system comprising a group of alternating current generators of various predetermined frequencies, and selective means for energizing the line circuit therefrom, in combination with a corresponding group of vibrators variously tuned to the may frequencies of said generators and means for subjecting said vibrators to the influence of the currents of various frequencies transmitted over said line circuit from the gen erators, together with an auxiliary circuit for each vibrator, a recording device for each vibrator and controlled by said auxiliary circuit, and means in connection with the motion of said vibrator for operatively closing said auxiliary circuit, together with means for damping the motion of said vibrator after the auxiliary circuit has been closed.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

ALF HJORT.

"Witnesses:

EMANUEL RosnNBERGER, JOHN J. HAYES. 

